1. Field of the Invention
The present invention relates to a novel strain of mycoplasma isolated from a patient with AIDS. The mycoplasma is closely related to a species of human mycoplasma, M. fermentans. Upon characterization of this mycoplasma, it may be classified as a unique strain within the species M. fermentans incognitus. This novel strain of nycoplasma is referred to hereinafter as the incognitus strain or M. fermentans incognitus.
The invention also relates to use of the mycoplasma M. fermentans incognitus as well as all strains of M. fermentans in detecting specific antibodies in sera of patients with AIDS or an acute fulminant systemic disease and/or animals and its use as a vaccine against infection by the mycoplasma. The invention further relates to incognitus strain-specific antibodies and cross-reactive which later break up into individual cells that are capable of passing through membrane filters of pore size 0.45 .mu.m or even 0.22 .mu.m.
A trilaminar cytoplasmic membrane contains sterols, phospholipid and proteins. Therefore, the cells are generally susceptible to polyene antibiotics and to lysis by digitonin.
Replication of the Mycoplasma genome may precede cytoplasmic division resulting in multinucleate filaments before individual cells are delimited by constriction. Budding can also occur.
Most Mycoplasma species are facultatively anaerobic, and all known species are chemoorganotrophic. The fermentative species of Mycoplasma utilize sugars such as glucose, while non-fermentative species can utilize arginine.
Known mycoplasmas may be grown on complex media, such as Hayflick medium, while fastidious mycoplasmas may be grown on diphasic SP-4 medium. The colonies are usually of the "fried egg" type, i.e., an opaque, granular central region, embedded in the agar, surrounded by non-granular surface growth. The optimal growth temperature of mammalian strains is 36.degree.-37.degree. C.
Many species of Mycoplasma produce weak or clear haemolysis which appears to be due to the secretion of H.sub.2 O.sub.2. This H.sub.2 O.sub.2 secretion is believed to be responsible for some aspects of the mycoplasmas' pathogenicity. Known mycoplasmas are commonly sensitive to chloramphenicol and tetracyclines.
The Mycoplasma genus currently consists of more than 60 known species which are differentiated on the basis of various tests, including utilization of glucose and mannose, arginine hydrolysis, phosphatase production, the "film and spots" reaction and haemadsorption. M. fermentans antibodies (i.e. antibodies to homologous antigenic determinants), including monoclonal antibodies of each, which are useful in detecting incognitus strain antigens in infected tissue of patients or animals. The invention also relates to incognitus strain-specific DNA probes which are useful in detecting incognitus strain genetic materials in infected tissues of patients or animals. Incognitus strain genetic materials may also be detected in infected humans or animals by using specific incognitus strain DNA sequences a homologous M. fermentans DNA sequences and the polymerase chain reaction ("PCR") (U.S. Pat. No. 4,683,202 incorporated herein by reference).
The ability to monitor AIDS or other acute fulminant systemic disease status can be of great value. In addition to improving prognostication, knowledge of the disease status allows the attending physician to select the most appropriate therapy for the individual patient, e.g. highly aggressive or less aggressive therapy regimens. Because of patient distress caused by more aggressive therapy regimens, it is desirable to distinguish those patients requiring such therapies. It has been found that M. fermentans incognitus is more directly associated and functional deficits of the infected organ systems and is capable of distinguishing such patients.
Mycoplasma is a genus of cell wall-less sterol-requiring, catalase-negative pathogens commonly found in the respiratory and urogenital tracts of man and other animals. The cells of Mycoplasma are typically non-motile and pleomorphic, ranging from spherical, ovoid or pear-shaped to branched filamentous forms. Filaments are the typical forms in young cultures under optimal conditions, which subsequently transform into chains of coccoid cells
Mycoplasmas are the smallest and simplest free-living organisms known. Mycoplasmas are not obligatory intracellular microorganisms and are usually found extracellularly, but are often found intracellularly in the infected tissues (Mycoplasma, Eds. Wolfgang, J. J., Willette, H. P., Amos, D. B., Wilfert, C. M., Zinsser Microbiology 19th Ed. 1988, Appleton and Lange, 617-623). The term mycoplasma apparently was first used by B. Frank in 1889 (Frank B., Dent. Bot. Ges., 7, 332 (1889) and Krass, C. J. et al., Int. J. Syst. Bacteriol. 23, 62 (1973)). Frank, after careful microscopic observation, began writing about invasion of plants (legume) by these microorganisms and stated: "the changed character of the protoplasm in the cortical cells arising from infection, I will designate as mycoplasma". Later, he had more explicitly defined mycoplasma as a mixture of small fungus-like microorganisms and cell protoplasm (Frank, B., Landwirt. Jahrb. 19, 523 (1890)). The description reflected the difficulty of differentiating this unique microorganism from the infected host cells morphologically.
Even today with electron microscopy, it is still often difficult to differentiate the mycoplasmas from the cellular protoplasmic processes or the subcellular organelles of the infected host, because ultrastructurally, these microorganisms have protoplasm-like internal structures and are bounded by only an outer limited membrane (unit membrane) without a cell wall. Thus, there have been few electron microscopic studies of mycoplasmas identified directly in the infected tissues of animals or humans.
It has been reported that ultrastructural examination of infected tissues has failed to localize the microbe, even in tissues where very high titers (&gt;10.sup.9 /gm) of microorganisms were recovered in culture (Elizan, T. S. et al., Pro. Soc. Exp. Biol. Med. 139, 52 (1972) and Schwartz, J. et al., Pro. Soc. Exp. Biol. Med. 139, 56 (1972)). Therefore, morphologically, the microbe might be mimicking certain normal cellular or subcellular structures in the infected host tissues and preventing direct identification.
In addition to the natural difficulty of morphological differentiation between the microorganisms and the protoplasm of infected cells, the often poorly preserved formalin-fixed clinical materials present further limitations to any attempt to directly visualize mycoplasma organisms in the tissues.